Submitted to: Meeting Abstract
Publication Type: Proceedings
Publication Acceptance Date: 5/1/1998
Publication Date: N/A
Citation: Interpretive Summary: One of the main problems limiting the ability to develope certain barley cultivars for malting and other industrial applications is that they may contain high levels of beta-glucans (fiber components), which are not broken down sufficiently during processing. One way to overcome this problem is to cause the seeds to produce more of a beta-glucanase enzyme, which breaks down the beta-glucans. However, the native enzyme is often i short supply or unable to withstand the high temperatures required in some processes. We have overcome this problem by introducing a heat-stable enzyme from the fungus Trichoderma reesi. The gene encoding the enzyme was previously cloned in such a way that the gene would only be turned on when the barley seed is germinating. The new glucanase that was produced by the seed was very heat-stable. The enzyme was able to withstand 2 hours of exposure to 65 degrees C, with no loss of activity, whereas 80% of the native barley glucanase was destroyed. This development will initially have the greatest impact on the malting and brewing industries by providing potential low glucan barley extracts. This also has potential use in the sweetener industry, and the same technology can also be adapted to produce small grains with better characteristics for poultry feed.
Technical Abstract: The gene for a thermotolerant endo-beta-glucanase from Trichoderma reesei was used to genetically transform the elite Finnish barley cultivar Kymppi and the non-malting barley cultivar Golden Promise. Only one transgenic plant resulted from particle bombardment-mediated transformation of Kymppi, whereas 250 bombarded Golden Promise embryos produced 37 plants. Extracts from the transformed barley seeds maintained 100% of glucanase activity after incubation for 2 hours at 65 degrees C. However, in untransformed seeds, the activity of native glucanase was reduced by 80%.